The EU-funded project, TECHNEAU, is intended (among other tasks) to develop a new water treatment simulator, in part to implement new process models to be developed within TECHNEAU. Before beginning any software development there has been a review of existing water treatment simulators, to identify what would be needed for a new system. This review has identified that there has been little usage of water treatment modelling, with the two main objections being the quantity of data required to calibrate the models, and the fragility of the models when applied outside the calibration region.